Method of making tubs



E. J. GRE IF METHOD OF MAKING TUBS Original Filed April 9, 1937 3 Sheets-Sheet 1 INVENTOR.

- 7 ATTORNEY.

Aug. 19, 1941.

E. J. GI'QEIF Original Filed April 9, 1957 3 Sheets-Sheet 2 Aug. 19', 1941. E. J. GREIF METHOD OF MAKING TUBS Original Filed April 9, 1937 3 Sheets-Sheet 3 Patented Aug. 19, 1941 I METHOD or MAKING TUBS Edward J. Greif, Chicago, Ill., assignor to Borg- Warner Corporation, Chicago, 111., a corporation of Illinois,

Original application April 9, 1937;

Serial No.

135,990, now Patent No. 2,225,988, dated December 24, 1940. Divided and this application November 30, 1938, Serial No. 243,170

Claims. (01. 153 -2) This invention relatesto large volume receptacles such as washing machine tubs,1and has. as its primary object to provide in a washing ma chine tub of the type wherein the side wall of the tub is connected to a mouthof reduced diameter by an upwardly and inwardly curving integral shoulder region, a sunken, concealed cover seat in which the cover may be supported with its edges concealed and its upper surface forming a smooth symmetrical continuation of said curved shoulder region. The present application is a division of my application SerialNo.1135,990, filed April 9, 1937, (Patent No. 2,225,988, granted Dec. 24, 1940).

, Washing machine tubs of the type having the reduced diameter mouth and the integral broadly curving shoulder region, commonly called bottle neck tubs have been known and produced prior to the present invention. In such a tub, the mouth is defined by a neck region which curves upwardly and outwardly. The cover, resting upon this upwardly projecting neck region, is spaced appreciably above the curved shoulder region. The present invention aims to improve upon a tub of this type by providing one in which the neck region instead of projecting upwardly, projects downwardly into the tub and is formed with a cover seat which is depressed below the rim of the shoulder region.

Another object of the invention is to provide a tub wherein the edge of the neck region is completely concealed and removed from the region of probable contact with clothes being inserted into or removed from the tub, so as to improve the appearance and eliminate the possibilityof cuttingor tearing the clothes, or injuring the operator. M

The problem of evolving a method for producing such a tub has proven to be an exceptionally difficult one. Accordingly, another object of the invention is to provide a method of successfully fabricating a tub having the characteristics above described, all from a single integral sheet of metal. l

To this end, the invention provides a method wherein thetub is first formed with the bottle neck shape in acordance with known practice,

and," utilizing the bottle neck construction as an intermediate stage in the formation of the ,turtle neck? tub of the present invention, additional operations are performed upon the neck region of the tub by means of which the neck region is turned back into the tub and formed with the desired sunken cover seat.

.Otherobjects-the advantages and. uses of the invention will become apparent after reading the following specification and claims, and after consideration of the drawings forming a part of the specification, wherein:

Fig. 1 is a schematic sectional view of a bottle neckftub forming an intermediate stage of construction of the tub of the present invention.

7 Fig. 2 is an enlarged sectional view of the shoulder and neck region thereof after a trimming operation has been performed.

Fig. 3 is a similar sectional view of the shoulder and neck region after the latter has been folded into the tub;

Fig. 4 is a sectional view of the shoulder and. neck region after the formation of, the offset which constitutes the cover seat. Fig. 5 is a vertical central sectional view of the completed tub.

Fig. 6 is a vertical sectional viewof a portion of the apparatus employed to give the receptacle the form shown in Fig. 3.

Fig. 7 is'a fragmentary plan view of the apparatus used to give the receptacle the form shown inFig. 4;

Fig. 8 is a vertical sectional view of the apparatus of Fig, '7 shown in an initial stage of operation.

Fig. 9 is a vertical sectional view of the apparatus of Fig. 7, shown in its final position of operation.

Fig. 10 is a vertical sectional view of the apparatus used to give the receptacle its final form shown in'an initial position of operation.

Fig. 11 is'a similar view showing the apparatus of Fig. 10 in its final position of operation; and

Fig. 12 isa fragmentary side elevation of the apparatus of Fig. 10, showing the means for ad- I justing the apparatus to its final position.

For the purposes of illustration, this invention will be described with reference to the formation of a washing machine tub, but it is understood that the invention can be embodied in other sheet metal receptacles which are of relatively large volume comparable to that of a washing machine tub, and accordingly involve the Problems met in the formation of a washing machine tub.

In forming a washing machine tub in accordance with the present invention, a sheet of. metal is first drawn with a straight cylindrical side Wall I5 and abottom I4 which may be punched to provide a central aperture 16 for reception of the agitator drive shaft and a drain cock aperture ll; In the next step of formation of the tub, the upper region of the side wall [5 iscurved upwardly and inwardly and thence curled outward- 1y to form a bottle neck I8 in accordance with the method described in my pending application Serial No. 91,269, filed July 18, 1936, entitled Machine for forming bottle necks upon sheet metal tubs (Patent No. 2,170,946, granted Aug. 29, 1939).

In the subsequent stages of formation of the tub, the material above the line A-A of Fig, 1 is superfluous, and the neck region, therefore, is

trimmed along the line AA to give it the formshown in Fig. 2. I I 7 Referring now to Fig. 2, it will be observed that the tub has been provided with a rounded shoulder l9, and a neck region including a substantially fiat portion 26, and an upturned portion 2|. Due to the fact that the neck region 2| is formed by decreasing the diameter of the tub, the thickness of the material in that region is-accordingly increased. Even though this portion is subsequently increased in diameter by being forced downwardly and outwardly, it will not thereby regain its original thinness. Accordingly, the thickness of the metal in the neck region 2| is reduced, preferably by the rolls which form such neck region.

In the next step of operation, the neck region 2| is folded axially into the tub to form the intermediate stage of construction shown in Fig. 3. The apparatus for performing this step of operation is shown in Fig. 6, and reference thereto is now made.

The in-folding apparatus comprises a base 22 which is cylindrical and has a flange 23 by which it may be secured to a suitable press (not shown). In its lower region, it has the bore 28 adapted to loosely receive the lower region of the side wall I of the tub. In its upper region it has an enlarged bore 25 connected to the bore 28 by a frusto-conical surface 26 and to its top surface 29 by a frusto-conical surface 21.

Located in the upper bore 25 is a collet ring 30 which has alternating notches 3| and 32 in its lower and upper regions respectively, rendering it contractile. Its normal interior diameter is approximately the same as that of the bore 28 so that the tub may be freely inserted through the ring. It is provided with inclined surfaces 33 and 34 adapted to coact with the inclined surfaces'26 and 21 in the base 22. Downward pressure against its upper end will cause it to contract under the camming action of the surfaces 33 and 34 against the surfaces 26 and 21, into constricting frictional engagement with the exterior surface of the side wall l5 of the tub, asshown in Fig. 6.

The shoulder IQ of the tub is adapted to be engaged by an annular holder 36 shaped to receive the upper region of the tub. A bottom support or pressure pad 46, urged upwardly by a plurality of compression springs 41 and guided by pins 48, serves to. urge the tub upwardly to maintain the shoulder I9 snugly against the holder 36, while the latter moves downwardly to engage the up-' per-end of'the collet ring 36 for moving said ring downwardly. The holder 36 is provided with'ears 31 and 38 adapted to register with ears 24 on the base 22, and to be connected thereto by locating pins. When thus properly assembled, the holder and base are mounted in a press having two rams to theouter of which the holder 36 is secured, and to the inner of which is secured a die member 39, which is guided in the holder 36 by surfaces 46 and 4| in the holder. Downward motion of the member is limited by a shoulder 42 on the holder. 36, which abuts a flange43 on the. die

member 39. The lower region of the holder 36 is shaped as at 44 to receive the upper end of the tub. The lower region of the die member I3 is recessed or cut away to provide a shoulder 45.

In the operation of the apparatus just described, in the starting position of the press, the holder 36 and die member 39 are raised above the collet ring 36 and base 22. Not being under compression, the ring 36 will be in its extended position. A tub in the intermediate stage of formation shown in Fig. 2 is inserted into the base 22 through the collet ring 30 until it rests upon the pressure pad 46. The press is then operated, whereupon the holder 36 descends, contacting the shoulder l9 of the tub and thereafter forcing the tub downwardly against the pressure pad 46 until it contacts the collet ring 36. During the remainder of its stroke, the holder 36 will force the collet ring 36 downwardly, and the latter will contract under the camming action of the surfaces 33 and 34 against the surfaces 26 and 21, into tight frictional engagement with the exterior surface of the tub. With the tub thus securely clamped, the inner ram of the press forces the die member 39 downwardly so as to fold the end region 2| of the shoulder region I9 axially into the tub. At its lower edge, the neck region thus formed will have the diameter of the reduced lower end region of the die element 39, whereas at the rim 16 formed by its junction with the shoulder region l9, it will have the slightly larger diameter of the intermediate region of the die element 39. Thus, the neck region is formed with a cylindrical portion 49 and a downwardly converging conical portion 56, in which there may be formed an offset to provide a seat, by die elements moving toward each other in a purely axial direction.

Pressure from the die element 39 is not transmitted to the pressure pad 46 owing to the absorption of such pressure by the frictional engagement of the collet ring 36 against the side wall of the tub. Accordingly, buckling of the side wall of the tub is completely avoided.

Upon the return stroke of the press, the inner ram raises the die element 39, stripping it from the tub while the latter is still held by the engagement of the holder 36 against its shoulder region l9. Subsequently, the holder 36 is raised, thereby relieving the collet ring 30 of downward pressure and allowing the latter to expand so as to release the tub, which may then be removed for further forming operations.

The seat forming apparatus is shown in Figs.

- 7, 8 and 9. It comprises a base 66 provided with an upstanding flange 6!. The base 66 is apertured at 62 to receive a bushin 63 in which a post 64 is slidable. Threaded upon the bushing 63 isa lower die 65 which comprises two concentric annular parts 66 and 61, the latter encircling the former and both adapted to be supported in a common plane against the fiat bottom of the base 60. The part 61 in turn is a split ring having a normal diameter greater than the outside diameter of the part 66. When expanded to such normal diameter, as shown in Fig. 8, it is adapted to loosely receive the shoulder region l9 of the tub in an inverted position. The outer surface 68 of the ring 61 and the inner surface 69 of the flange 6| are shaped conically, and conform to each other so that downward pressure on the ring 61 will cause it to contract under the camming action of said surfaces. The ring 61 preserves the form of the shoulder l9 of the tub.

An upper die 14, severed circumferentially into pivoted in bearings 16 secured as by bolts 11 to the. die element 66. As shown in Fig; 7, the jaws T are relatively closely spaced circumferentially, although the spacing is sufficient to; permit a bolt 19 to pass between two adjacent jaws. The

bolts 19 are extendedthrough suitable apertures in a pressure plate l9which overhangs the pivots l6, and thence between pairs of adjacent jaws 15.

Their ends are provided with nuts 90 of sufilcient diameter to straddle the twoadjacent jaws T5 and to engage the same for raising them to the inoperative position shown in dotted lines in Fig. 9. i 1

The pressure plate 19 receives the post 54 and abuts a shoulder 8| thereon, so that downward motion of the post will move the pressure plate downwardly. Guide posts 82 extending through apertures 83 in the pressure plate 19, and threaded into the lower die element 66, maintain the pressure plate 19 in proper position. Compression springs 84, interposed between the pressure plate 19 and the lower die element 56 and receiving the guide posts 82, maintain the pressure plate in properposition. The springs 84 serve to return the pressureplate 19 to its starting position after it has been lowered by the posts 54. The upward movement of the pressure plate is limited by theheads B5 of the posts 82. In moving upwardly; the pressure plate 19 contacts the heads 86 of the bolts 19 prior to being stopped against the heads 85, so as to, liftthe jaws I5. When the jaws are in their raised position, shown in dotted lines, the tub may be lifted without its neck region contacting said jaws. On the contrary, when the jaws are lowered to their fullline' position as, shown, they extend radially over the neck region soas to engage the frictional upper die element .14 and totransmit downward pressure, thereto.

central aperture. l6 of, the tub, so as to be connected to a suitable press, for. applying downward pressure thereto. For tubs not having such an aperture, the power can be applied to the lower end of the post 64.

The seat forming operation can best be described with reference to Fig. 8. A tub having the form shown in Fig. 3 is inverted, and the sections of the upper die M are inserted in the annular space between the in-folded neck region and the side wall of the tub. If the neck region were not made conical as at 59, downward pressure of the upper die would cause this portion to buckle. The conical form, however, causes the end of the neck portion 59 torest upon the rounded corner 81 of the upper die 14 and to slide therearound without buckling when pressure is applied. 7

The inverted tub with the upper die 14 in place is then inserted into the supporting ring 61 of the lower die 65, the ring 61 at the time being expanded so as to readily receive the tub. The post 64 is then lowered, causing the jaws 15 to spread outwardly and downwardly into contact 150 The post 64 may extend upwardly through the with the upper face of the "upper die 14. Continued downward movement of the pressure plate 19 causes the upper die 14 to contact the rim 10 of the tub, pinching the same between itself andflthe supporting ring 61. From this point downward, the ring 61 contracts and the die 14 and dieelement 96 gradually form the conical portion 50 of the in-folded neck region between them until at the bottom of the stroke, thering 61 is fully contracted and the die elements 14 and 66 have completely come together against the neck region 59 to form the same to the shape shownin Fig. 4. Upward movement of the post 64 then raises the jaws l5, relieving the upper die M of pressure, and near the top of the stroke, the IingB'I is raised by means of chains (not shown) thereby spreading it and simultaneously stripping the tub I5 from the portion .66 of the lower die 95. The upper die 14. is then removed from the tub l5 by inserting a suitable toolinto groove 89 provided for that purpose and pulling, it fromrim 19 of the tub. The tub now has the form shown in Fig. 4 and is ready for the curling operation. a a a 5 The last step in the'formation cf the, cover seat is to curl the offset, end region T3 of the neck radially outwardly so as to. remove its edge from the region of probable contact with clothes being inserted intoand removed from the tub. The apparatus for doing this is shown in Figs. 10, 11 and 12, and comprises .a circular track .90 adapted to fit into the neck region 49 of the tub,

and to abut the seatll, and a curling roll 9|. provided with a cylindrical portion 92 adapted,

to engage the track 99. The roll9| is mounted on a bracket 99 securedto an arm 94 mounted on a shaft 95. The track 90 is supported-on a camming ring 96 by means of rollers, 91 which.

thetrack 9|).is held against rotation with respect tothe frame. Illl. by means of pins 12.; Anoperating lever I93, secured to the ring 96, provides,

the means for oscillating said ring.

The arm 94 is secured on the shaft 95 by means of a nut I95 threaded on toa threaded portion I94 of the shaft 95. i Onlyone arm and one roll are used in the apparatus so, that the tub |5 may be readily slipped between the roll and the track.

In the curling operation, the has the form shown in Fig. 4, is placed upon the track 9|), again in an inverted position. The

shaft 95 is rotated, carrying with it the arm 94 'andthe roll 9|, and the operating lever I93 is gradually advanced until the cylindrical portion 92 of the roll 9| contacts the track 99, as a result of the raising of the track 99 under the camming action of the roller 91 in the slot 98. At the end of the movement, the edge 13 will have been turned outwardly by the sloping contour of the roll 9|.

When the curling is completed, lever I03 is moved in the opposite direction, thereby lowering the track 90 and permitting the tub [5 to be removed from the apparatus. The tub now has th completed form shown in Fig. 5. i

It will be apparent from the foregoing description that by the practice of my method it is postub, which new curved shoulden-all in :one integral piece. Prior to .the'present-invention, it was'considered necessary to employ-a separatesheet of metal for the necksandseatregions of a receptacle of this general shape. Furthermore, the invention provides for curling theedge of the seat, which is usually sharp. and rough. as aresult of .the forming operation', radially outwardly to a position where it will notl'comelinzcontact with clothing orlother materialswhich may be pulled across the seat. The metalof the seat is not unduly strained and is free from undesirable Wrinkles. Therinvention utilizesdies. of greater diameter. than the diameter of the seat and arranges for the insertion of them and the means for applying pressure to-them through the reduced mouth of the tub.

One of. the big problems solved by the invention is that of folding the neck region axially into the tub-without buckling or otherwise deforming the sidewall of .the tub under the tremendous pressure required for such folding operation. This problem is solved by frictionally engaging the side wall of the tub by mechanism operated in timed relation with the stroke of the drawing die, so as to absorb the axial pressure of the drawing die inthe upper region of the side wall of the tub, and prevent its being transmitted to the bottom ofthetub.

The finished tub; shown in Fig. 5, is adapted to receive a cover I01 having a suitable reinforcing rim l06- adapted to be entirely concealed within the neck region 49 of the tub when resting upon the seat H, so that the upper surface of the cover may be flush with and form a smoothly curving continuation of the shoulder l9, thereby presenting a very artisticand stream-lined contour of the tub as a whole. This eiTect is very desirable, and the present invention makes it possible and practical.

Iclaim:

1. The steps in the method of forming a cover seat in a-large-volume'receptacle, consisting in forming a bottle-neck in the open end of the receptacle byrolling said open end inwardly, and thereafter folding the end, region of said bottleneck axially into' the receptacle by means of purely axial pressure directed toward the bottom of the receptacle, while frictionally engaging the lateral exterior surface of the receptacle so as to absorb said axial pressure to prevent deformation of the side wall of the receptacle under said pressure.

2. The steps in'themethod of forming a receptacle from a single sheet of metal which consists in forming a bottle-neck in the open end of the receptacle by rolling said open end inwardly, thereafter folding the end region of said bottleneck axially into'the receptacle, by purelyaxial pressure directed toward the bottom of the receptacle, thereafter forming the end region of the in-folded'neck portion ina forming die to form an inwardly projecting offset therein, and thereafter rolling the'end region'of the offset portion radially outwardly so as to remove the edge thereof .from the region of .probable contact with articles being introduced into and removed from the receptacle.

3. The steps in the method of forming a largevolume receptacle from a single sheet of metal in a cup-shaped initial stage of formation which consists in forming a bottle-neck in the open end region of the partially formed receptacle by rolling the .said open end region inwardly, thereafter folding the end region of said bottle-neck axially into the receptacle by purely axial pressure directed toward the bottom of the receptacle, to form a cylindrical portion and a conical portion, thereafter forming the conical portion in a forming. die to form an inwardly offset region therein providing a seat, and thereafter rolling the end portion of said offset region radially outwardly so as to remove the edge thereof from the region of probable contact-therewith by articles being introduced into and removed from the receptacle.

4. The steps in the method of forming a cover seat in a receptacle which consist, in the order named, in rolling the open end region of the receptacle inwardly to from a neck region, folding the end portion of said neck region axially inwardly in spaced relation to the side wall of the receptacle, inverting the receptacle, supporting an upper die between said in-folded neck region and the side wall of the receptacle, and directing downward pressure against said die and thereby forcing said in-folded neck region against a lower die to form an inwardly ofiset region providing a cover seat therein, and thence rolling the end portion of said offset region radially outwardly.

5. The steps in the method of forming a cover seat in a relatively large-volume receptacle, which consist, in the order named, in rolling the open end'region of said receptacle inwardly to form a bottle-neck, trimming said neck, folding the end region of said neck axially into the receptacle in spaced relation to the side wall of the receptacle, inserting a sectional annular die between the in-folded neck region and the wall of the receptacle, and directing downward pressure against said die while the rim of the receptacle is supported in a lowerdie, whereby to form said neck region between said dies with an offset region providing a cover seat.

EDWARD J. GREIF'. 

